设置变量时游戏代码中断 [英] Game code breaking when setting variable

问题描述

这个游戏代码看起来不错，但它不起作用:

This game code seems fine, but it's not working:

//Get canvas and context
var canvas = document.getElementById('canvas');
var ctx = canvas.getContext('2d');

//Capture keypresses
var keys = [];
document.onKeyDown = function (e) {keys[e.keyCode] = true;};
document.onKeyUp = function (e) {keys[e.keyCode] = false;};

//Set game variables
var characters;
characters.charList = [];
var player = {};

//Character constructor
function Character (Name, Strength, Speed, Intelligence, Reflexes, Age, Height, Weight, Weapon, UsesMagic, MagicType, Armor, Hair, Eyes, Skin, Clothes, Species, Type, Accessories) {
        this.name = Name;
        this.strength = Strength;
    this.speed = Speed;
    this.intelligence = Intelligence;
    this.reflexes = Reflexes;
    this.age = Age;
    this.height = Height;
    this.weight = Weight;
    this.weapon = Weapon;
    this.usesMagic = UsesMagic;
    this.magicType = MagicType;
    this.armor = Armor;
    this.hair = Hair;
    this.eyes = Eyes;
    this.skin = Skin;
    this.clothes = Clothes;
    this.species = Species;
    this.type = Type;
    if (Accessories) {
            this.accessories = Accessories;
    }
    characters.charList[characters.charList.length] = Name;
}

characters.Xantar = new Character('Xantar', 1, 1, 1, 1, 1, 1, 1, 'sword', true, 'derp', [], 'hair is brown\?', 'duh', 'foo', [], 'animale', 'wolf', []);
alert(characters.Xantar.weapon + '   ' + characters[0].type);

//Activate mainloop and get value for pausing purposes
var mainloopInterval = setInterval(mainloop, 5);
//Main game loop
function mainloop(){

}

程序似乎停在:

characters.charList = [];

我只是没有看到这里的问题.这是相关的 HTML:

I simply don't see the problem here. Here is the relevant HTML:

<canvas id='canvas' style='border:1px solid black;'>Your browser does not support canvas. Please update your browser.</canvas>

注意:我在 JSFiddle 上运行它.如果有人能在这里帮助我，我将不胜感激.这是链接:https://jsfiddle.net/q6vdph1p/14/.

Note: I am running this on JSFiddle. If anyone could help me here, I would be really grateful. Here is the link: https://jsfiddle.net/q6vdph1p/14/.

推荐答案

如前所述，您需要先将一个对象分配给 characters 变量，然后才能访问其中的属性.

As noted before, you need to assign an object to your characters variable before you'll be able to access properties in it.

只需用 var 字符声明； 将分配给它 undefined 的值并尝试访问 undefined.charList 并分配一个空数组它会失败.

Just declaring it with var characters; will assign it the value of undefined and trying to access undefined.charList and assign an empty array to it will fail.

一种更合适、抗故障且可读的声明方式是构建空数据结构，如下所示:

A more proper, fail resistant, and readable way of declaring it would be building the empty data structure, like so:

var characters = {
    charList: []
};

此外，使用array.push() 添加到数组的末尾比使用array.length 索引更安全，即

Also, adding to the end of an array is more safe using array.push() than indexing by array.length, i.e.

characters.charList.push(Name);

而不是

characters.charList[characters.charList.length] = Name;

这篇关于设置变量时游戏代码中断的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！